What happens when pollinators lose their flowers? A new study suggests some answers

 

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Pollinators such as bees and butterflies are highly dependent on flowers to provide nectar as food; at the same time, those plants are reliant on the pollinators for reproduction.  Over the past few decades, declines in both flower and pollinator diversity and abundance have prompted ecologists to wonder about the consequences of flower loss for pollinator communities and for plant pollination.

In a ground breaking new study, a team from institutions in the Czech Republic and the University of Northampton in the UK have published the results of experiments that seek to answer these questions.  Led by PhD researcher Dr Paolo Biella, the team performed experiments in both countries that involved temporarily removing thousands of flower heads from grassland plant communities.  They assessed how the pollinator assemblage responded to their removal, and how effectively the remaining flowers were pollinated.  The team focused on generalist plant species that support the majority of pollinators within a community because these have traditionally been less well studied than highly specialised relationships.

The results are published today in the open access journal Scientific Reports and provide the first demonstration of the ways in which pollinators flexibly adjust their behaviour when faced with a sequential loss of resources.  This flexibility is constrained by the type of flowers they visit, however:  pollinators will tend to switch to flowers of a similar shape to the ones that have been lost.  From the plant’s perspective, things are less clear: the patterns of pollination for the remaining species were idiosyncratic and not as predictable.  Some plants received more pollination during the experiment than before, others less.

For the first time we are seeing the consequences of sudden loss of flowers for both the pollinators and the plants in a habitat.  That the pollinators can respond flexibly to this loss is a welcome indication that these insects might be more resilient to sudden changes than we had thought.  However, the erratic pollination of the flowers shows that there is a great deal of random chance within these ecological systems that is not easily predictable.  In the same week that the UN’s Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) Global Assessment Report on Biodiversity and Ecosystem Services was published, our study reminds us that there is much that we do not currently understand about the consequences of sudden changes in the natural world.

One of the team’s recommendations is that pollination-generalist plant species should be given much more attention in conservation assessments than has previously been the case.  These plants are at the core of plant-pollinator communities and without them the rarer and more specialised species could not exist.

Details of the study are as follows:

Biella P., Akter A., Ollerton J., Tarrant S., Janeček Š., Jersáková J. & Klecka J. (2019) Experimental loss of generalist plants reveals alterations in plant-pollinator interactions and a constrained flexibility of foraging.  Scientific Reports 9: 1-13

Here’s the abstract:

Species extinctions undermine ecosystem functioning, with the loss of a small subset of functionally important species having a disproportionate impact. However, little is known about the effects of species loss on plant-pollinator interactions. We addressed this issue in a field experiment by removing the plant species with the highest visitation frequency, then measuring the impact of plant removal on flower visitation, pollinator effectiveness and insect foraging in several sites. Our results show that total visitation decreased exponentially after removing 1-4 most visited plants, suggesting that these plants could benefit co-occurring ones by maintaining high flower visitor abundances. Although we found large variation among plant species, the redistribution of the pollinator guild affected mostly the other plants with high visitor richness. Also, the plant traits mediated the effect of removal on flower visitation; while visitation of plants which had smaller inflorescences and more sugar per flower increased after removal, flower visitors did not switch between flower shapes and visitation decreased mostly in plants visited by many morpho-species of flower visitors. Together, these results suggest that the potential adaptive foraging was constrained by flower traits. Moreover, pollinator effectiveness fluctuated but was not directly linked to changes of flower visitation. In conclusion, it seems that the loss of generalist plants alters plant-pollinator interactions by decreasing pollinator abundance with implications for pollination and insect foraging. Therefore, generalist plants have high conservation value because they sustain the complex pattern of plant-pollinator interactions.

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Biodiversity and climate change: a hierarchy of options

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The related issues of how to conserve biodiversity and reduce the impacts of climate change have never had such a high public profile as they do at the moment.  The activities of Extinction Rebellion caught the attention of the media around the world, for example here in London.  Numerous organisations, cities, regions and countries have declared a Climate Emergency.  And IPBES – the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Serviceshas released a summary of its first global assessment with the full report due later this year, and explicitly makes the link between conservation of biodiversity and reducing the effects of climate change.

Timed to coincide with all of this, the University of Cambridge has announced that it is setting up a Centre for Climate Repair in order to explore hi-tech “fixes” to climate change, such as spraying sea water into the atmosphere in order to reduce warming at the poles, and sucking CO2 out of the air using large machines.  I think it’s fair to say that this was met with some scepticism on social media; here’s some examples:

Other people have pointed out that nature-based solutions are the most likely to be successful, and provide a boost for biodiversity at the same time:

All of this reminds me of the Waste Hierarchy in its various iterations – you know the sort of thing – “Reduce > Reuse > Recycle”, where reduction in waste produced is best, followed by reuse of waste resources, with recycling being the least good option (but still better than just land-filling the waste).  As far as the link between conservation of biodiversity and reduction of the effects of climate change goes, there’s a parallel hierarchy – see the image at the top of this post – that sets out the order of priorities:

PROTECTION of ecosystems using the full force of national and international laws and conventions has got to be the top priority.  Otherwise any of the other activities will result in, at best, humanity running to catch up with what the world is losing.  Let’s stop cutting down ancient forests and degrading peatlands that have accumulated millions of tons of carbon over thousands of years!

FIX – by which I mean the kind of hi-tech solutions proposed above – should be the lowest priority: they do little or nothing directly for biodiversity and there is no compelling evidence that they will even work as intended.

Between these two are RESTORATION of currently degraded habitats (such as re-wetting peatlands as in the Great Fen Project) and PLANTING of trees, which can be a form of habitat restoration under some circumstances.  Large scale examples of this include

Grain for Green – China’s attempt to restore vegetation to abandoned farmland to reduce soil erosion and flooding.

Great Green Wall – a multinational initiative in Africa aimed at restoring the vegetation on the southern edge of the Sahara to combat desertification and mitigate climate change.

While doing a bit of research for this blog post* I became aware that a Conservation Hierarchy has already been developed by the Convention on Biological Diversity but that really only deals with habitat destruction, mitigation of destructive activities, etc.  What I’m suggesting is related more to the direct link between conservation of biodiversity and mitigation of climate change.  So what to call this particular hierarchy?  Perhaps the BioCC Hierarchy?  Can anyone suggest a better name?  Maybe it doesn’t need a name at all, it just needs people to be aware of it and for governments to act logically.

 

*I googled the term “Conservation Hierarchy” – you get the quality of research you pay for on this blog….

 

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When did the flowering plants evolve? Two new studies come to different conclusions

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The angiosperms (flowering plants) are far and away the most diverse group of plants ever to have evolved.  There are an estimated 350,000 to 370,000 species, more than all other groups of plants (ferns, conifers, cycads, mosses, etc.) combined, living and extinct.  The origin of the flowering plants was termed an “abominable mystery” by Charles Darwin – or perhaps it wasn’t: see this essay by Prof. Richard Buggs for an alternative view of what Darwin was describing, and this paper by Prof. William Friedman giving a different interpretation.

These disagreements about what Darwin meant are as nothing compared to disagreements about when the flowering plants actually evolved and how we interpret fossils and evidence from molecular phylogenies.  Two new studies illustrate this point: they use some of the same information to come to completely different conclusions.  I’ve copied the details and abstracts below, with links to the originals, and emphasised the areas of disagreement in bold text.  And I’m going to leave it at that; I don’t have a horse in this race and I have no idea which (if either) is correct.

There are, however, profound implications for understanding when and how relationships between flowering plants and their pollinators evolved, as I noted in my recent review of pollinator diversity.  If the much earlier, Triassic origin of the angiosperms is correct then perhaps the earliest flowering plants did not co-opt pollinators that were already servicing gymnosperms.  Perhaps the relationships between plants and pollinators originated with the (Triassic) angiosperms and the gymnosperms subsequently evolved to exploit this.  My feeling is that only more, better fossils will provide definitive answers.

Here’s the details of the studies:

Coiro et al. (2019) How deep is the conflict between molecular and fossil evidence on the age of angiosperms? New Phytologist

Abstract: The timing of the origin of angiosperms is a hotly debated topic in plant evolution. Molecular dating analyses that consistently retrieve pre‐Cretaceous ages for crown‐group angiosperms have eroded confidence in the fossil record, which indicates a radiation and possibly also origin in the Early Cretaceous. Here, we evaluate paleobotanical evidence on the age of the angiosperms, showing how fossils provide crucial data for clarifying the situation. Pollen floras document a Northern Gondwanan appearance of monosulcate angiosperms in the Valanginian and subsequent poleward spread of monosulcates and tricolpate eudicots, accelerating in the Albian. The sequence of pollen types agrees with molecular phylogenetic inferences on the course of pollen evolution, but it conflicts strongly with Triassic and early Jurassic molecular ages, and the discrepancy is difficult to explain by geographic or taphonomic biases. Critical scrutiny shows that supposed pre‐Cretaceous angiosperms either represent other plant groups or lack features that might confidently assign them to the angiosperms. However, the record may allow the Late Jurassic existence of ecologically restricted angiosperms, like those seen in the basal ANITA grade. Finally, we examine recently recognized biases in molecular dating and argue that a thoughtful integration of fossil and molecular evidence could help resolve these conflicts.

 

Li et al. (2019) Origin of angiosperms and the puzzle of the Jurassic gap. Nature Plants

Abstract: Angiosperms are by far the most species-rich clade of land plants, but their origin and early evolutionary history remain poorly understood. We reconstructed angiosperm phylogeny based on 80 genes from 2,881 plastid genomes representing 85% of extant families and all orders. With a well-resolved plastid tree and 62 fossil calibrations, we dated the origin of the crown angiosperms to the Upper Triassic, with major angiosperm radiations occurring in the Jurassic and Lower Cretaceous. This estimated crown age is substantially earlier than that of unequivocal angiosperm fossils, and the difference is here termed the ‘Jurassic angiosperm gap’. Our time-calibrated plastid phylogenomic tree provides a highly relevant framework for future comparative studies of flowering plant evolution.

 

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Is the angry response of (some) environmentalists in the aftermath of the Notre Dame fire reasonable?

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Last night Karin and I returned from two weeks of field work plus a period of writing in Tenerife.  The first week was devoted to our annual University of Northampton undergraduate field course which I’ve written about before – see this recent book review for instance.

I don’t normally watch much television when I’m in Tenerife; we tend to get back from field work early evening, jump in the shower, then go for a beer and a meal, then early to bed for field work the next day.  But there were two bits of TV that I made a point of viewing, and actually for the same reasons: news reports about the fire that severely damaged Notre Dame Cathedral and David Attenborough’s documentary about the current effects of climate change.  Both of these were about the destruction of heritage (cultural and natural) and how this affects people.  I have to say that I shed a tear watching them.

The response of some billionaires and large companies, offering millions of Euros towards Notre Dame’s restoration, was criticised by some environmentalists and others concerned with social justice.  Here are some examples:

https://www.joe.ie/amp/life-style/notre-dame-feature-665670

Over at the Ecology for the Masses blog, Sam Perrin in turn criticised these responses, suggesting that “What environmentally-minded people need to start doing is examine the other cause. Why do they get more attention? How have they gone about making their issue so ubiquitous? Try and examine WHY the Notre Dame Cathedral has received over 1 billion USD in reconstruction pledges when the Great Barrier Reef languishes every day.”

Jeremy Fox of the Dynamic Ecology blog clearly agrees  with this sentiment (read his comments) and posted a link to Sam’s piece.  I have to say that I got a bit irritated at Jeremy’s use of the phrase “pet causes”, and responded that: “I wouldn’t describe wholesale destruction of habitats, over-exploitation of natural resources, species’ extinction rates orders of magnitude higher than the background, environmental degradation that is affecting people’s health and livelihoods, and the accelerating effects of climate change as a “pet cause”. We’re not talking about raising funds for new books in the local library here!”

If you follow that series of comments and replies on Dynamic Ecology you’ll see that Jeremy pushed back strongly against my response, and I replied in return.  I stand by what I said though, that people do not react to these sorts of events logically, they react emotionally.  Hence the initial emotional outpouring of offering millions of Euros to restore Notre Dame is matched by an equally emotional response of “think of all of the other things that we could do with that money”.   The response from environmentalists and others was a reasonable one, as was the offer of millions of Euros for Notre Dame.  Both are equally valid.  Whether both are equally “important” is something that we could debate forever and I urge you to read through the posts and comments and make up your own mind.

On our last full day in Tenerife Karin and I explored an area of xerophytic scrub vegetation that surrounded a small rocky hill (see image below).  On top of the hill is a set of ancient rock carvings produced by the indigenous Guanches, one thousand years ago or more (the image at the start of this post).  The Guanches had positioned some of the rocks so that they produced different notes when struck.  It was clearly a site that had deep significance to these people prior to the European conquest of the islands.  However the site is completely unprotected and there’s been no effort to interpret what is a culturally important bit of archaeology – such carvings are not common in the Canary Islands.  In addition the surrounding vegetation is being slowly degraded by illegal tipping of rubbish.  These struck me as a depressingly fitting accompaniment to the subject of this post.

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The persistent crisp packet: 23 years in the environment and still going strong

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Last night Karin and I returned from Buxton in the Peak District where we had hired a cottage and assembled most of our kids and their partners for a weekend get together.  During a walk in the surrounding countryside I spotted this crisp packet sticking out of the ground.  From the typography of the logo I could tell it was old and a bit of internet sleuthing suggests that it was from a special limited edition produced to commemorate the UEFA 1996 European Football Championship.  So it’s been hanging around in the environment for about 23 years, hardly decaying, possibly releasing harmful chemicals into the environment.

Needless to say, I took it home and binned it.  But this one crisp packet is a microcosm of an enormous global problem of single-use plastic waste that is not being disposed of properly or recycled.  It’s a particular issue in the developing world where wastes management infrastructure is simply not able to cope with the volume of plastic bags and packaging, as I saw recently on my trip to Nepal:

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This sort of waste is more than just unsightly: it is harming the world’s ecosystems and the biodiversity they contain.  Manufacturers of plastic need to step up and address this issue.  Action is happening as I know from discussions with colleagues such as Prof. Margaret Bates and Dr Terry Tudor who are actively researching, educating and advising in this area.  But I worry that it may be too little and too late.

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Beekeeping at 7000 ft: Nepal field work part 4

On the last day of field work, while we were waiting for a bus to take us back down to Kathmandu, I spotted some small bee hives next to one of the houses belonging to the local Tamang peoples:

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With a few minutes to spare before the bus left, I quickly investigated and discovered that only one of the hives was actually in use:

But interestingly, the bees inside where the native Asiatic or eastern honeybee (Apis cerana) rather than the European or western honeybee (A. mellifera) that is more familiar in Europe.  The bees are a bit smaller and more distinctively striped than their western counterpart:

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There didn’t seem to be much around for the bees to forage on, just a few flowering mustard plants, so I suspect that they were travelling some distance to find nectar and pollen:

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At this altitude of 2092 masl, or about 7000 feet, the winters are long and cold and the summers dry and hot, so the bees must be tough if they are kept there all year round.  I wonder if A. mellifera would survive these conditions?

All too soon the bus driver sounded his horn and it was time to go; an interesting encounter with a bee species I’d not previously seen.

 

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A unique oak: Nepal field trip part 3

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One of the plants that really intrigued me during my time in Nepal was a species of evergreen oak that is native to the Himalayas and nearby mountainous areas of Asia.  It goes by the name of Quercus semecarpifolia and, as far as I am aware, has no common English name.  Two things surprised me about this species.

First of all, it is heterophyllous, meaning that its leaves come in more than one type.  Leaves close to the ground are spiky and look a lot like those of holly (Ilex spp.) which is what I thought they were when I first saw them:

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Leaves higher up on the plant have far fewer, if any, spikes:

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One of the things I discussed with the students was the job of scientists to identify patterns and to develop hypotheses about processes, i.e. what had caused those patterns.  In this case, after some discussion, we decided that the heterophylly was probably an adaptation to defend the leaves against small browsing mammals such as deer (thanks to Narayan for this image):

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The other thing that interested me about the oak was its overall growth form, which was tall (they grow to 30m) with rather short, stubby branches, very distinctive from a distance:

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The tree were especially striking in the evening mist:

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They look as though someone has been out with a chainsaw and trimmed them, but that’s not the case, they naturally grow that way.  The best hypothesis that we could come up with is that this is an adaptation that prevents the trees from accumulating large, heavy loads of snow which could result in branches breaking.

I’ve never seen this growth form, not heterophylly, in any other oak species, but Quercus is a large genus of about 600 species, so I wouldn’t be surprised if similar species exist.

Part 4 to follow.

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Tracks in the snow: Nepal field trip part 2

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As I mentioned in part 1 of this series of posts, there was unseasonable snow at higher elevations during my trip to Nepal.  This made walking a bit treacherous and at night the temperatures dropped to below freezing.  However it did mean that we could see where animals had been moving about the landscape, including the red panda (Ailurus fulgens) which made the tracks in the image above.

Tracks from a total of seven different types of mammals were recorded, such as black bear:

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And the pika, a member of the group that includes rabbits and hares:

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No yetis, but some very yeti-like, moss covered trees:

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There were some very tough flowers dealing with the snow, such as this Primula denticulata:

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And what I think might be a gentian (Gentiana sp.):

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Walking conditions were very challenging at times:

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But the students really enjoyed it:

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The dining rooms of the hostels in which we stayed were cosy:

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And of course the landscapes were fabulous:

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Part 3 to follow

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Crows and kites over Kathmandu: Nepal field trip part 1

 

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On Monday I returned from a 10 day trip to Nepal to support an undergraduate field course run by one of the University of Northampton’s partner colleges, NAMI.  It was my first time in that country, actually my first time in the Indian subcontinent, and it was quite a trip.  I want to share some thoughts and experiences over a few blog posts.  They will be light on text and heavy on imagery, because Nepal is such a spectacular country in so many ways, and the Kathmandu Valley has an abundance of ancient temples, palaces and other sites, many of which survived the 2015 earthquake that flattened more recent buildings:

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But first, what of those crows and kites?  They are actually Black kites (Milvus migrans), dozens of them, and hundreds of Indian house crows (Corvus splendens), all providing an important service in Kathmandu: clearing some of the rubbish from the streets.  They were especially spectacular in the evening, around 5.30 pm, when I would watch them circling and moving towards their nightly roost:

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It’s a really stunning urban wildlife spectacle that none of my pictures do justice to, so here’s a close up of one of the crows:

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Kathmandu has a serious problem with waste and pollution, as do many large cities in that region:

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But the NAMI campus itself is very nice, clean and well presented:

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And it has wildlife of its own, including and array of birds, butterflies and bees, and at least one species of lizard:

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But beyond that, the staff and students I worked with were just great, a real pleasure to meet, the staff committed and the students very engaged with their studies:

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This one was taken the day that we set off for the field trip, in a bus that was driving us from Kathmandu to Kutumsang at 2470 metres above sea level.  The two NAMI staff members who led the field trip, Narayan Prasad Koju and Sanu Raja Maharjan, are both highly experienced Nepalese ecologists:

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We spent one night at Kutumsang then trekked to Mangengoth at 3420 masl, then Thadepati (3690 masl).  It was unseasonably cold up there and quite a lot of snow was still on the ground.  At that point I started suffering from altitude sickness and was happy to descend back to Kutumsang.  During our trek the students established 20m x 20m quadrats at 200 m intervals and recorded woody plant diversity and abundance, and which plants were in flower.  In addition they recorded the tracks and scats of any mammals they encountered.  Here are some shots of the students in action and the general landscape:

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Part 2 to follow.

 

 

 

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Book review: Vegetation of the Canary Islands by Marcelino J. del Arco Aguilar and Octavio Rodríguez Delgado (Springer 2018)

Figure 1 - Tenerife 2008 - students on the Aeonium field - lo res

 

This is the text from a book review that’s published this week in The Niche, which is the British Ecological Society’s members’ bulletin.


 

The Canary Islands mean many things to different people.  To the millions of holiday makers each year they are places of relaxation, of sun, sand, sea and holiday shenanigans.  To Charles Darwin, writing during the early weeks of the Beagle voyage, they were the “long wished for object of my ambition”.  Having read accounts of Tenerife by earlier explorers such as Alexander von Humboldt, Darwin was excited to have the opportunity to visit “perhaps one of the most interesting places in the world”.  Sadly it was not to be: an outbreak of cholera back in Britain meant that the Beagle’s crew would have to be quarantined for 12 days before they could disembark.  Captain FitzRoy was not prepared to do this and so the Beagle moved on.

I recount this story to my University of Northampton students each April when we visit Tenerife for our annual field course.  Referring to it as “Darwin’s Unrequited Isle”, I point out how fortunate they are to live at a time when a short plane flight can take them from the UK to such a fascinating natural laboratory of in situ evolution and biogeographical processes (Figure 1).  We’ve been going to the island since 2003 and we’re certainly not the only European university to do so, I know of at least five others in the UK alone.

To ecologists and those interested in natural history the Canary Islands are a fascinating mixture of the exotic and the banal.  Endemic succulent spurges (Eurphorbia spp.) grow with non-native prickly pear cacti (Opuntia spp.), traditional cafes serving tapas and local wines butt up against sports bars providing a full English breakfast with a pint of Carlsberg for less than five Euros.  The rapid development of tourism on the islands means that there are enormous pressures on land for building apartment complexes, as well as on water resources, energy generation and wastes management.  The islands are a laboratory for sustainable development as much as they are for evolution.

The literature on Canary Island ecology, biogeography and conservation has grown quickly, much of it fuelled by the education opportunities afforded by the islands.  As the authors of Vegetation of the Canary Islands note, the book is both “a synthesis of numerous publications….[and data and experience].…from many years of teaching and research…at the University of La Laguna”.  This fieldwork-focused, dusty boots approach to understanding the Canary Islands flora is apparent throughout the volume which has clearly been a labour of love for the highly knowledgeable authors.

The book is divided into eight chapters, plus appendices. Chapter 1 entitled Geographic Framework gives a summary of the physical geographical and geological context of the islands in relation to the rest of Macaronesia, and explains something of the human history of indigenous peoples (collectively termed the Guanches) and the later European colonisers.  The population of the islands (estimated to be 2.1 million in 2016) swells by an order of magnitude with close to 15 million tourists visiting that same year.  One of the attractions for north Europeans is dealt with in Chapter 2 Canary Climate   Although categorised as subtropical, the weather can be hugely variable, especially on the more mountainous islands; we have experienced blistering heat, torrential rain and snow storms in April in the higher reaches of Tenerife (which at 3,718 m is the second highest island in the world).  Irregular and geographically sporadic rainfall is a particular feature. This leads neatly into Chapter 3 on Bioclimatology that relates this climatic variability to the plant communities of the islands.  A sense of how complex this is can be gauged from Table 3.4 that lists 57 different bioclimatic combinations and their associated vegetation types, many of which overlap.

Chapter 4 on Biogeography considers how the islands have been colonised over a time scale that goes back more than 65 million years, including islands that no longer exist, having eroded and become submerged, but which in the past acted as stepping stones for colonisation of species from the continent and between archipelagos.  This includes some fascinating speculation regarding the role of much earlier island groups to the south west of the Canary Islands that may have allowed exchange of plants between Africa and the Americas, and that could explain some intriguing disjunctions in current distributions.  There is also a very useful summary of endemic genera.

Chapter 5 Other Floristic Considerations initially looks at the non-vascular flora of algae, fungi, lichens and bryophytes, which is rich (5508 species compared to 2091 vascular plants) though the rate of endemism is not so high.  There is then more comparison of diversity and endemism between plant families and islands, followed by a summary of molecular taxonomic findings.  Given how short it is I think that this chapter could easily have been incorporated into the previous one, though that’s a minor criticism.

The bulk of the book (from pages 83 to 308) is taken up by Chapter 6 Vegetation of the Canary Islands which provides a very detailed arrangement of the flora in the classical Braun-Blanquet form using names adapted from the species that are characteristic of that community (“Nerio-Tamaricetea”, “Morello fayae-Pinetum canariensis”, etc.).  To ecologists not trained in this tradition, and more used to the National Vegetation Classification (NVC) scheme familiar to us in Britain, this terminology can seem a little daunting.  Fortunately the introductory section provides a broader classification of the vegetation into categories such as “Euphorbia scrub and shrublands”, “Laurel forest”, etc.  This is a good stepping off point for anyone interested in understanding the vegetation further, before plunging into the subsequent sections that examine these communities in great detail.  The later coloured maps of the potential natural vegetation of the islands, without anthropogenic interference, are especially useful for teaching.

This leads us into Chapter 7 which deals with Changes in the Natural Landscape Through Human Influence.  As the authors point out, people have influenced the vegetation since the earliest period of human settlement on the islands, about 1000 BCE, as these arrivals brought with them livestock such as goats, sheep and pigs, as well as useful plants.  However this process was hugely accelerated from the 15th century onwards as Europeans rapidly conquered the islands and cleared large areas of forest, as well as introducing many more invasive species.  The chapter ends with a very thought provoking section on climate change and its likely effects.

Chapter 8 considers the Conservation Status of the Canarian Flora and Vegetation, providing a history of how protected areas were set up, including the designation of seven UNESCO Biosphere Reserves and two Natural World Heritage Sites. Lists of protected plant species and their various designations are also provided and there’s a short summary of invasive species.

The four appendices give: (1) an over view of the phytosociological scheme for understanding the communities; (2) a short history of botanical exploration of the islands,  which emphasises just how many botanists and ecologists the archipelago has attracted over the years; (3) notes on the ethnobotany of the islands; (4) and a long list of relevant literature, extending over 18 pages.  A weakness of the book is that the literature is not cited within the text, presumably for reasons of readability.  This does make it much more difficult to track specific sources of information back to its origin, however. The text concludes with two indices, one phytosociological and one taxonomic.

The book is well illustrated with both colour and black and white photographs and figures, though the quality of some of these in the e-book version that I was provided with for this review were not as sharp as they could have been.  I hope that the print version is better quality.

Vegetation of the Canary Islands will appeal to anyone interested in the ecology of this most fascinating of archipelagos, though at £119.99 for the hardback it is expensive.  It should certainly be bought by any library of a university that carries out teaching and research on the islands.  The earlier and later chapters will be of most use for students and their teachers; the central sections on phytosociology really require more specialist knowledge, though there’s a lot of fascinating ecology in there for the patient reader.  One thing that did surprise me about the book is that the role of fire in determining the type of vegetation in an area is hardly considered, except as it relates to the negative consequences of large wild fires.  Yet many of these habitats must have burned naturally before people arrived on the islands, as evidenced by the amazing ability of Pinus canariensis to re-sprout after it has burned (Figure 2).

During our field course in Tenerife the students and staff spend a week exploring the different plant communities of the island, as well as bird and bee behaviour, and half a day of sea mammal observation.  I’ve used it as an opportunity to conduct long term data collection that otherwise would never get funded (see Figure 1), and some of this research has already been published.  Two other books that I’ve found useful and which should be on the bookshelves of anyone wishing to learn more about Darwin’s Unrequited Isle are: Natural History of Tenerife by Philip and Myrtle Ashmole (2016) and Tenerife Nature Walks by Sally Lamdin-Whymark (2013).  Both are available on Amazon.

Figure titles:

Figure 1:  University of Northampton students surveying a population of Aeonium urbicum, Santiago del Teide, Tenerife, 2008.  This monocarpic species is the subject of long-term data collection to assess what triggers flowering.

Figure 2:  Post-fire regeneration of Canary Island Pine (Pinus canariensis) on Tenerife 2008-2017.  Most species of pines are killed by fire; P. canariensis is one of the few that can re-sprout following a burn.

Figure 2 - Pine forest burn sequence.jpg

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